this is two weeks old, but apparently #intel are incompetent at keeping backups of their important old things: 'Intel branded desktop motherboards were discontinued in 2013. We no longer have the motherboard-specific BIOS source code, build environment, and tools to build new BIOS releases with the microcode update for some discontinued products.'
(source: https://www.intel.com/content/www/us/en/support/articles/000026630/boards-and-kits/desktop-boards.html)